Uneven brake wear AGAIN😡

[arctictraveller]

When servicing my van pre-trip, I usually check the rate of wear of the brake pads. A few days ago that inspection showed that the rear brake pads on the inside were nearly completely worn, (again) while the outside were at least 3/4 the thickness of new. This is not a new problem, and I’ve tried to address it in the past by replacing the brake lines with the theory that the old rubber lines may have collapsed inside preventing the release of pressure. Another theory is that one of the pistons in the calipers hangs up. Anyway, after about only 25K miles, once again I’m doing a total brake rebuild in the rear. I am replacing absolutely everything, rotors, calipers, pads, wheel bearing seals, and parking brake shoes ( that’s another story) but I’d love to hear other opinions on why this may happen. Another theory is that the ABS unit may not be releasing the pressure fully, but shouldn’t that cause even wear on the brake pads? Has anyone found a solution to this common problem?

[The_Vermonster]

I would suspect the slide pins. I think they're the weakest part of the system. Often people will put a grease that swells the rubber and prevents the caliper from sliding.

[boywonder]

Originally Posted by The_Vermonster

I would suspect the slide pins.

me too.......that's the usual suspect 99% of the time.


Unless your calipers have pistons on both sides of the rotor..those don't float and in that case uneven wear is usually caused by a sticky piston.

[arctictraveller]

Originally Posted by boywonder

me too.......that's the usual suspect 99% of the time.
Unless your calipers have pistons on both sides of the rotor..those don't float and in that case uneven wear is usually caused by a sticky piston.

I forgot to mention that the slider pins were well greased and moved freely. I’m going with the sticky piston theory and got replacements under warranty from O’Reilly. This is the third set I’ve had on there from three different rebuilders. When I walked into the auto parts store and set the calipers on the counter the guy immediately said “sticky piston“? it seems to be a pretty common problem. I’d prefer to buy a new but no one manufactures them.

Well I am whining, I replaced the parking brake shoes due to a leaking oil seal, but the new shoes had so much lining on them the disc wouldn’t fit back over the shoes until I put the adjuster in the lathe and shortened it by a quarter of an inch so the shoes could come in further. That raises the question about contact area on the drum, if the radius is different the contact area is going to be less, resulting in a crappy parking brake.

Well at least there’s still parts available, I prefer the current situation to nonavailability any day. But…….come on

[boywonder]

It's kinda late now but with the caliper off you could have someone lightly step on the brake while you watch the pistons........sometimes you can get a couple pushes out of them and get an idea of what's happening with the pistons.......push them back in with a C clamp and repeat....

[arctictraveller]

Originally Posted by boywonder

It's kinda late now but with the caliper off you could have someone lightly step on the brake while you watch the pistons........sometimes you can get a couple pushes out of them and get an idea of what's happening with the pistons.......push them back in with a C clamp and repeat....

It’s not too late, they are still hanging there, so I could do that, great idea. I wonder though if they don’t get slightly crooked in the bore as they wear, and bind up under pressure?

[The_Vermonster]

Rebuilt calipers suck, especially the autoparts store brands. Most of those are reman'd by Cardone anyway.

When I couldn't get new, I bought reman Motorcraft Calipers. They are made by TRW, the OE maker of calipers. So as far as I'm concerned, that's as close to new as you can get.



When you said you replaced the rubber brake hoses, did you do the one that connects the axle to the hard lines on the frame?

[Nrobert10]

I’ve had the same problem multiple times and a couple caliper freezing while traveling. I recently bought the crazy expensive SSBC calipers. Night and day difference in stopping power!

[ShuttlePilot]

I've read through this a few times but maybe I'm still missing it. Is the uneven wear happening on one rear wheel or is it happening on both driver and passenger sides?

[arctictraveller]

Originally Posted by ShuttlePilot

I've read through this a few times but maybe I'm still missing it. Is the uneven wear happening on one rear wheel or is it happening on both driver and passenger sides?

Mostly on the drivers side but somewhat on the passenger side too